The Collaborative International Dictionary of English v.0.48:

Chaldean \Chal*de"an\, a. [L. Chaldaeus.]
   Of or pertaining to Chaldea. -- n.
   (a) A native or inhabitant of Chaldea.
   (b) A learned man, esp. an astrologer; -- so called among the
       Eastern nations, because astrology and the kindred arts
       were much cultivated by the Chaldeans.
   (c) Nestorian.
       [1913 Webster]

WordNet (r) 3.0 (2006):

Chaldean
    adj 1: of or relating to ancient Chaldea or its people or
           language or culture [syn: Chaldean, Chaldaean,
           Chaldee]
    n 1: a wise man skilled in occult learning [syn: Chaldean,
         Chaldaean, Chaldee]
    2: an inhabitant of ancient Chaldea [syn: Chaldean,
       Chaldaean, Chaldee]